The overall objective of this proposal shall be to evaluate the potential role of tumor specific helper factor(s) in augmenting both the in vitro and in vivo responsiveness of syngeneic lymphoid cells toward three syngeneic tumors. The tumor models selected for study are the lethal line-10 hepatocarcinoma and L2C leukemia and the nonlethal line-1 hepatocarcinoma. All of these tumors are syngeneic in the strain-2 guinea pig. Tumor specific helper factors will be isolated by use of a recently developed methodology by which eucaryotic cells can be coupled to an insoluble support matrix. Immunoadsorbents of this type have previously been shown to select for highly reactive molecules with specificity for the coupled cell types, and have been employed to isolate specific helper factor(s) in the line-10 hepatocarcinoma model. The specific aims of the proposal are: 1) To isolate and characterize helper factors for the line-10, line 1 and L2C tumors, by use of these cellular immunoadsorbents. 2) To evaluate the cytotoxic augmenting capacity of each of these helper factors and to determine their tumor specificity in vitro. 3) To evaluate their specificity and potential tumor suppressive capacity in vivo. Thus these studies will fully evaluate the potential use of cellular immunoadsorbents for isolation and characterization of three separate tumor specific helper factor(s) and should determine the potential therapeutic value of each in well characterized experimental tumor models.